The invention relates in general to permanent magnets and more particularly to a mangle magnetic structure motor and generator.
It is often desirable to have magnetic structures that are not too brittle and will stand up to excessive stress. It is also desirable to employ less torque for rotating cylindrical rods so that activating motors can be smaller and less expensive.
The structure of the present invention is derived from the magic ring configuration described in many papers and previous patents, which is also known as the Halbach structure. The magic ring or cylinder is a cylindrical permanent magnet shell which is magnetized in the plane transversely to the cylindrical axis so that the direction of magnetization xcex3 with respect to the polar plane varies twice as rapidly as the azimuthal coordinate, xcfx86, according to the formula:
xcex3=2xcfx86
The polar plane is the plane that includes the cylindrical axis and the polar lines. Such as arrangement produces very high fields in its interior in proportion to its mass and bulk and is depicted in FIG. 1. Referring now to FIG. 1, there is depicted a magic ring segment 10 having a central cavity 11, annular shell 12, a magnetic field, indicated by large arrow 13, direction of magnetization indicated by smaller arrows 14 and polar plane 15. For example, at point A, the coordinate, xcfx86, is 22.5xc2x0 while the direction of magnetization, according to this formula is 45xc2x0.
The magic ring may be approximated by arranging transversely magnetized parallel cylindrical rods in a bundled cylindrical shell depicted in FIG. 2, known as a xe2x80x9cmangle.xe2x80x9d Mangle structures are described in [J. M. D. Coey and O. Cugat, 13th Int. Workshop on Rare Earth Permanent Magnets and Their Applications, Birmingham, U.K., P4, 11-14, September (1994) and] O. Cugat, P. Hanson and J. M. D. Coey, IEEE Transactions Magnetics, MAG-30 (1994), pg. 4602. Although mangles produce less field for their mass and bulk than cylinders, they are much easier to manufacture because they are composed of identical parts all magnetized in the same way. Referring now to FIG. 2, there is depicted a magic mangle structure [20], with a shell 20 composed of a group of magnetic rods 21 that are magnetized as indicated by small arrows 22 and a magnetic field represented by large arrow 23. Because shell 20 [23] is composed of a series of rods it is lighter than the solid structure annular shell 12, which is depicted FIG. 1.
The present invention provides mangle cylindrical magnetic structures that overcome the problems, difficulties and shortcomings associated with brittle magnetic structures that cannot withstand excessive stress. The present invention""s mangle cylindrical magnetic structures are lighter and therefore require less torque for rotating cylindrical rods permitting widespread use with smaller and less expensive activating motors, without suffering from the disadvantages and shortcomings of prior art structures. By advantageously bundling a set of transversely magnetized parallel cylindrical rods into a rotatable magnetic shell enclosing a cavity having wires parallel to the principal axis, the present invention provides a mangle generator that is simple and inexpensive to manufacture and operate.
Other references on mangle and magic ring magnetic structures are [K. Halbach, Nuclear Instr. And Math, 169(1980) p. 1.; K. Halbach, Nuclear Instr. And Math, 187 (1981) p. 109; H. Zijlstra, Philips J. Research, 40 (1985) p. 259; and] H. A. Leupold et al., J. Appl. Phys., 63 ([1989] 1988) p. [3487] 3987 and 64 ([1959]1988) p. 5994.
It is an object of the present invention to provide mangle cylindrical magnetic structures.
Another object of the present invention is to provide mangle cylindrical magnetic structures by bundling at least two concentric sets of transversely magnetized parallel cylindrical rods into a rotatable magnetic shell enclosing a cavity having wires parallel to the principal axis.
These and other objects are advantageously accomplished with the present invention by bundling a set of transversely magnetized parallel rotatable cylindrical rods to form a magnetic shell enclosing an interior cavity. The interior having wires parallel to the principal axis, and two semicircular sections which are connected to a load outside the shell. In alternative embodiments, the present invention provides a structure for each end of the bundles to bear a load between semi-cylinders and for two sets of concentric transversely magnetized parallel rotatable cylindrical rods.